net/quic/crypto/crypto_handshake_message.cc

// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/quic/crypto/crypto_handshake_message.h"

#include "base/strings/stringprintf.h"
#include "base/strings/string_number_conversions.h"
#include "net/quic/crypto/crypto_framer.h"
#include "net/quic/crypto/crypto_protocol.h"
#include "net/quic/quic_socket_address_coder.h"
#include "net/quic/quic_utils.h"

using base::StringPiece;
using base::StringPrintf;
using std::string;
using std::vector;

namespace net {

CryptoHandshakeMessage::CryptoHandshakeMessage()
    : tag_(0),
      minimum_size_(0) {}

CryptoHandshakeMessage::CryptoHandshakeMessage(
    const CryptoHandshakeMessage& other)
    : tag_(other.tag_),
      tag_value_map_(other.tag_value_map_),
      minimum_size_(other.minimum_size_) {
  // Don't copy serialized_. scoped_ptr doesn't have a copy constructor.
  // The new object can lazily reconstruct serialized_.
}

CryptoHandshakeMessage::~CryptoHandshakeMessage() {}

CryptoHandshakeMessage& CryptoHandshakeMessage::operator=(
    const CryptoHandshakeMessage& other) {
  tag_ = other.tag_;
  tag_value_map_ = other.tag_value_map_;
  // Don't copy serialized_. scoped_ptr doesn't have an assignment operator.
  // However, invalidate serialized_.
  serialized_.reset();
  minimum_size_ = other.minimum_size_;
  return *this;
}

void CryptoHandshakeMessage::Clear() {
  tag_ = 0;
  tag_value_map_.clear();
  minimum_size_ = 0;
  serialized_.reset();
}

const QuicData& CryptoHandshakeMessage::GetSerialized() const {
  if (!serialized_.get()) {
    serialized_.reset(CryptoFramer::ConstructHandshakeMessage(*this));
  }
  return *serialized_.get();
}

void CryptoHandshakeMessage::MarkDirty() {
  serialized_.reset();
}

void CryptoHandshakeMessage::SetTaglist(QuicTag tag, ...) {
  // Warning, if sizeof(QuicTag) > sizeof(int) then this function will break
  // because the terminating 0 will only be promoted to int.
  COMPILE_ASSERT(sizeof(QuicTag) <= sizeof(int),
                 crypto_tag_may_not_be_larger_than_int_or_varargs_will_break);

  vector<QuicTag> tags;
  va_list ap;

  va_start(ap, tag);
  for (;;) {
    QuicTag list_item = va_arg(ap, QuicTag);
    if (list_item == 0) {
      break;
    }
    tags.push_back(list_item);
  }

  // Because of the way that we keep tags in memory, we can copy the contents
  // of the vector and get the correct bytes in wire format. See
  // crypto_protocol.h. This assumes that the system is little-endian.
  SetVector(tag, tags);

  va_end(ap);
}

void CryptoHandshakeMessage::SetStringPiece(QuicTag tag, StringPiece value) {
  tag_value_map_[tag] = value.as_string();
}

void CryptoHandshakeMessage::Erase(QuicTag tag) {
  tag_value_map_.erase(tag);
}

QuicErrorCode CryptoHandshakeMessage::GetTaglist(QuicTag tag,
                                                 const QuicTag** out_tags,
                                                 size_t* out_len) const {
  QuicTagValueMap::const_iterator it = tag_value_map_.find(tag);
  QuicErrorCode ret = QUIC_NO_ERROR;

  if (it == tag_value_map_.end()) {
    ret = QUIC_CRYPTO_MESSAGE_PARAMETER_NOT_FOUND;
  } else if (it->second.size() % sizeof(QuicTag) != 0) {
    ret = QUIC_INVALID_CRYPTO_MESSAGE_PARAMETER;
  }

  if (ret != QUIC_NO_ERROR) {
    *out_tags = NULL;
    *out_len = 0;
    return ret;
  }

  *out_tags = reinterpret_cast<const QuicTag*>(it->second.data());
  *out_len = it->second.size() / sizeof(QuicTag);
  return ret;
}

bool CryptoHandshakeMessage::GetStringPiece(QuicTag tag,
                                            StringPiece* out) const {
  QuicTagValueMap::const_iterator it = tag_value_map_.find(tag);
  if (it == tag_value_map_.end()) {
    return false;
  }
  *out = it->second;
  return true;
}

QuicErrorCode CryptoHandshakeMessage::GetNthValue24(QuicTag tag,
                                                    unsigned index,
                                                    StringPiece* out) const {
  StringPiece value;
  if (!GetStringPiece(tag, &value)) {
    return QUIC_CRYPTO_MESSAGE_PARAMETER_NOT_FOUND;
  }

  for (unsigned i = 0;; i++) {
    if (value.empty()) {
      return QUIC_CRYPTO_MESSAGE_INDEX_NOT_FOUND;
    }
    if (value.size() < 3) {
      return QUIC_INVALID_CRYPTO_MESSAGE_PARAMETER;
    }

    const unsigned char* data =
        reinterpret_cast<const unsigned char*>(value.data());
    size_t size = static_cast<size_t>(data[0]) |
                  (static_cast<size_t>(data[1]) << 8) |
                  (static_cast<size_t>(data[2]) << 16);
    value.remove_prefix(3);

    if (value.size() < size) {
      return QUIC_INVALID_CRYPTO_MESSAGE_PARAMETER;
    }

    if (i == index) {
      *out = StringPiece(value.data(), size);
      return QUIC_NO_ERROR;
    }

    value.remove_prefix(size);
  }
}

QuicErrorCode CryptoHandshakeMessage::GetUint16(QuicTag tag,
                                                uint16* out) const {
  return GetPOD(tag, out, sizeof(uint16));
}

QuicErrorCode CryptoHandshakeMessage::GetUint32(QuicTag tag,
                                                uint32* out) const {
  return GetPOD(tag, out, sizeof(uint32));
}

QuicErrorCode CryptoHandshakeMessage::GetUint64(QuicTag tag,
                                                uint64* out) const {
  return GetPOD(tag, out, sizeof(uint64));
}

size_t CryptoHandshakeMessage::size() const {
  size_t ret = sizeof(QuicTag) +
               sizeof(uint16) /* number of entries */ +
               sizeof(uint16) /* padding */;
  ret += (sizeof(QuicTag) + sizeof(uint32) /* end offset */) *
         tag_value_map_.size();
  for (QuicTagValueMap::const_iterator i = tag_value_map_.begin();
       i != tag_value_map_.end(); ++i) {
    ret += i->second.size();
  }

  return ret;
}

void CryptoHandshakeMessage::set_minimum_size(size_t min_bytes) {
  if (min_bytes == minimum_size_) {
    return;
  }
  serialized_.reset();
  minimum_size_ = min_bytes;
}

size_t CryptoHandshakeMessage::minimum_size() const {
  return minimum_size_;
}

string CryptoHandshakeMessage::DebugString() const {
  return DebugStringInternal(0);
}

QuicErrorCode CryptoHandshakeMessage::GetPOD(
    QuicTag tag, void* out, size_t len) const {
  QuicTagValueMap::const_iterator it = tag_value_map_.find(tag);
  QuicErrorCode ret = QUIC_NO_ERROR;

  if (it == tag_value_map_.end()) {
    ret = QUIC_CRYPTO_MESSAGE_PARAMETER_NOT_FOUND;
  } else if (it->second.size() != len) {
    ret = QUIC_INVALID_CRYPTO_MESSAGE_PARAMETER;
  }

  if (ret != QUIC_NO_ERROR) {
    memset(out, 0, len);
    return ret;
  }

  memcpy(out, it->second.data(), len);
  return ret;
}

string CryptoHandshakeMessage::DebugStringInternal(size_t indent) const {
  string ret = string(2 * indent, ' ') + QuicUtils::TagToString(tag_) + "<\n";
  ++indent;
  for (QuicTagValueMap::const_iterator it = tag_value_map_.begin();
       it != tag_value_map_.end(); ++it) {
    ret += string(2 * indent, ' ') + QuicUtils::TagToString(it->first) + ": ";

    bool done = false;
    switch (it->first) {
      case kICSL:
      case kIFCW:
      case kCFCW:
      case kSFCW:
      case kIRTT:
      case kKATO:
      case kMSPC:
      case kSWND:
        // uint32 value
        if (it->second.size() == 4) {
          uint32 value;
          memcpy(&value, it->second.data(), sizeof(value));
          ret += base::UintToString(value);
          done = true;
        }
        break;
      case kKEXS:
      case kAEAD:
      case kCGST:
      case kCOPT:
      case kLOSS:
      case kPDMD:
      case kVER:
        // tag lists
        if (it->second.size() % sizeof(QuicTag) == 0) {
          for (size_t j = 0; j < it->second.size(); j += sizeof(QuicTag)) {
            QuicTag tag;
            memcpy(&tag, it->second.data() + j, sizeof(tag));
            if (j > 0) {
              ret += ",";
            }
            ret += "'" + QuicUtils::TagToString(tag) + "'";
          }
          done = true;
        }
        break;
      case kCADR:
        // IP address and port
        if (!it->second.empty()) {
          QuicSocketAddressCoder decoder;
          if (decoder.Decode(it->second.data(), it->second.size())) {
            ret += IPAddressToStringWithPort(decoder.ip(), decoder.port());
            done = true;
          }
        }
        break;
      case kSCFG:
        // nested messages.
        if (!it->second.empty()) {
          scoped_ptr<CryptoHandshakeMessage> msg(
              CryptoFramer::ParseMessage(it->second));
          if (msg.get()) {
            ret += "\n";
            ret += msg->DebugStringInternal(indent + 1);

            done = true;
          }
        }
        break;
      case kPAD:
        ret += StringPrintf("(%d bytes of padding)",
                            static_cast<int>(it->second.size()));
        done = true;
        break;
      case kUAID:
        ret += it->second;
        done = true;
        break;
    }

    if (!done) {
      // If there's no specific format for this tag, or the value is invalid,
      // then just use hex.
      ret += "0x" + base::HexEncode(it->second.data(), it->second.size());
    }
    ret += "\n";
  }
  --indent;
  ret += string(2 * indent, ' ') + ">";
  return ret;
}

}  // namespace net